Stereotype matrix



Patented Feb. 24, 1925.

UNITED STATES FRANZ WILHELM WIRTI'I, OF DRESDEN, GERMANY.

STEREOTYPE MATRIX.

No Drawing.

To all 1071011246" may concern Be it known that I, FRANZ VILHELM burn, a citizen of th Republic of Germany, residing at Seminarstrasse 22, Dresden-A, Germany, have invented certain new and useful Improvements in Stereotype Matrices, of which the following is a specification.

The usual stereotype matrices are, as is wellknown, worn to such an extent after a few castings have been taken therefrom that sharp impressions of the faces of the letters cannot be obtained This is due to various causes which are further explained in the following description of the new method.

The new method has for its object the production of a matrix which will permit of the production of many castings without the impression of the face of the letters being altered in any way even; for example, which will remain in its original condition after 100 castings have been taken.

The new method consists in this that the flongs-prepared in the usual manner-are treated by spraying, painting or the like on the lHlPlGSSlOD-SlClG with a liquid, which contains heat-insulating means (borax and am- 1noniumsulphate) and fermentation preventing means (for example carbolic acid), and on i the rear side with paste, to which preferably a medium preventing fermentation is added, and to the paste layer is applied a covering sheet of paper or like material which is impenetrable by the paste. The flong thus treated is thereupon applied to the forme, treated in the press under pres sure and then, while still under pressure, is subjected by heating to a short drying operation of about one or two minutes dura tion.

It has already been proposed to introduce the matrix pulp by beating, calendering or pressing into the forms and then to take the impression under high pressure and thereafter to dry the matrices so formed together with the type forme utilizing heating and pressure for this purpose. This method not only requires much time but does not produce a matrix capable of withstanding many casting operations. To beat it in the matrix pulp must be moistened very much and the drying operation consequently takes a long time and must be carried through until the drying is completed, because otherwise the matrix would become too brittle. If the matrix is completely dried Application filed March 8, 1922. Serial No. 542,120.

in 'the air or in a drying oven it shrinks and produces indistinct and altered letters. If, on the other hand, the flong is calendered dry a quite sharp impression is not obtainable and sharp letters cannot be obtained therefrom. It has also been proposed to produce flongs from separate sheets of paper saturated with paste, by gumming the sheets to one another alternately with tissue paper to one another and then drying in the air.

It is clear that with such a process a great deal of time is required for the production of the-fiongs. Such flongs, moreover, are hard so that in dry impressing they adhere to the type while in use of such matrices in moist condition, the characters are pressed through, i.e., the separate layers of paper are cut so that in casting th liquid type metal penetrates between the separate layers.

Compared with such methods in the pres ent method the impression side of the matrix is rendered insensitive to the influence of heat. Moreover the flong is rendered flexible just at the moment the impression is taken and the means for rendering it flexible, namely the paste, is so distributed in the flong that it reaches the critical parts, that is the edges of the letters and the like. Thus a kind of cushion is formed which permits of obtaining a sharp impression which is retained on drying. In casting from such matrices the paste materials thus distributed form a rib, which acts as a stiffening and prevents the contraction of the matrix The whole of the process can be carried out in a very short interval of time, the application of the liquid to the impression side and the application of the paste to the rear only requiring a few movements of the hand and, the impression and drying being matters only of a few minutes. The matrix produced by this process can be used either at once or after an interval of time. More over, between the separate castings suitable intervals of time may elapse.

The process may be carried out as follows :-On the impression side of the fiong of pulp produced in the usual manner there is finally distributed by spraying or otherwise a liquid composed of 1 kg. water, 50 gr. ammonium-sulphate, 15 gr. borax, 20-gr. boric acid and 3-gr. carbolic acid. The rear side of the flong is then coated with matrix paste to which some dextrin has been added. On the coating thus formed is placed a sheet of unsized paper which may also be slightly coated on its adjacent surface with paste. The flong thus produced is placed with its impression side on the type and introduced into a press. The impression isproduced in this press, means for heating being provided so that the impression and dryingare effected at the same time. It is sufficieiit if the flong with the torme remains in the press for one or two minutes. After the removal from the press the matrix thus completed is quite ready for use.

Having now particularly described and, ascertained the nature of our said invention and in what manner the same is to be performedwe declare that what we claim is A method of producing stereotype impressions, consisting in treating the impression side of the flong, prepared in the usual manner, by spraying, painting or the like With liquid containing a heat-insulating medium,

(borax and ammonium-sulphate) and a termentatiompreveiiting medium, such as carbolic acid, and treating the flong on the rear side avith paste to which suitably a termentation-preventing medium is added, and applying to the paste layer a covering sheet of paper or like material which is impenetrable by the paste, whereupon the flong thus treated is placed in the torme and subjected to pressure in the press, and while the pressure is maintained is subjected to heating and a short drying operation of one or two minutes duration.

In testimony whereof I afiiX my signature in presence of two witnesses.

FRANZ WILHELM W IRTH.

Witnesses RICHARD IFFERTE, JOHANNA SCHAFER. 

